Conventionally, there has been known a sample testing system which tests a sample such as blood or urine collected from a human subject such as a patient. In the sample testing system, the sample is automatically transported to a testing apparatus which carries out a first test (first-round test) on the sample. When the first-round test result of the sample departs from a normal range, the sample is automatically transported to the testing apparatus which carries out a second test (retest) on the sample.
In US Patent Publication No. 2006-216199, a system is disclosed which includes a first blood analysis apparatus for carrying out a primary analysis, a second blood analysis apparatus for carrying out a secondary analysis, and a transport apparatus which has a function to transport a rack accommodating sample containers to each sample supply position of the first blood analysis apparatus and the second blood analysis apparatus. In the system, the primary analysis by the first blood analysis apparatus is carried out on all the samples, and the secondary analysis by the second blood analysis apparatus is carried out only on the sample for which it is determined that a detailed analysis needs to be carried out based on the primary analysis result.
In WO 2005/093433, a sample transport module is disclosed which is configured to be used with each of plural sample processing instruments of a multi-instrument clinical work cell. The sample transport module includes a sample aspiration station for supporting a sample container rack on a position to which an aspiration probe of the sample processing instrument approaches, and a housing for partitioning an buffer for supporting the plural sample container racks on a position from which the sample container rack is removed from the sample transport module. The sample transport module transports a received sample container rack to the sample aspiration station, and delivers the sample container rack to the buffer after the sample aspiration from the sample container in the sample container rack. In addition, the sample transport module can return the sample container rack, which has been delivered to the buffer, to the sample aspiration station for reflex or repeat testing, when a first test result indicates that a second aspiration of a specific sample needs to be carried out or when the first test result is obviously in error. In the sample transport module, an X/Y movable truck is provided to press the sample container rack into the buffer. The X/Y movable truck can take out the final sample container rack in a waiting line in order to carry out the repeat testing or the reflex testing.
However, in the system disclosed in US Patent Publication No. 2006-216199, there is a problem that the system is complicated because the second blood analysis apparatus for the secondary analysis is necessary.
In the sample transport module described in WO 2005/093433, when it takes a longer time than expected until the reflex testing or the repeat testing is determined to be necessary, the sample container rack holding the sample which requires the reflex testing or the repeat testing may be pushed into the buffer and another sample container rack may exist behind the sample container rack at the time when the determination result is obtained. A technique for automatically returning the sample container rack to the sample aspiration station is not disclosed in WO 2005/093433.